The Invisalign Teen brand of clear teeth aligners hopes a new guarantee program will help it take a larger bite of the orthodontia market.

Invisalign promises that if teen patients or their parents aren't satisfied within the first six weeks of treatment, participating orthodontists will switch the patients to traditional metal wires and brackets at no cost.

The deal is being offered in four cities, including Houston, and is available to teenage patients who start treatment before February.

Invisalign had a 6 percent share of the teen market in 2010, according to company data.

"I am pleased to see there is a satisfaction guarantee that backs the treatment ... and look forward to more parents being open to trying Invisalign Teen treatment," Dr. Brad Jennings of Jennings Orthodontics in Houston said in a statement.